Gomori‐positive astrocytes: Biological properties and implications for neurologic and neuroendocrine disorders

Abstract

Granule laden astrocytes exhibiting an affinity for chrome alum hematoxylin and aldehyde fuchsin (Gomori stains) have been described in the periventricular brain of all terrestrial vertebrate species examined to date including humans. The astrocytic inclusions are rich in sulfhydryl groups, emit an orange-red autofluorescence, and stain intensely with diaminobenzidine, a marker of endogenous peroxidase activity. The distinct autofluorescence pattern and the absence of neutral lipid, acid phosphatase, and beta-glucuronidase activity exclude lipofuscin or lysosomes as components of these astrocytic granules. The emission of orange-red autofluorescence and the nonenzymatic nature of the peroxidase activity implicate the presence of porphyrins and metalloporphyrins such as heme as major constituents of these cytoplasmic gliosomes. The role of Gomori-positive astrocytes under normal and pathologic conditions is incompletely understood. In vivo, numbers of astrocytic granules increase as a function of advancing age, in response to chronic estrogen stimulation, and following X-irradiation. In vitro, these cells accumulate with increasing time in culture and following exposure to the sulfhydryl agent, cysteamine. Gomori-positive astrocytes may supply heme to neurons for the synthesis of cytochromes, catalases, and other heme enzymes. They may play a role in photostimulation of sexual cyclicity, the promotion of neuritic development, the degradation of toxic lipoperoxides, and the metabolism of various neurotransmitters. Conversely, these cells may contribute to the pathogenesis of several neurologic and neuroendocrine disorders. Examples of the latter include a) augmentation of goldthioglucose neurotoxicity, b) induction of hypothalamic anovulation and reproductive failure, c) exacerbation of porphyric encephalopathy, and d) potentiation of parkinsonism and other free radical-related neurodegenerations.

Degeneration and proliferation of astrocytes in the mouse dentate gyrus after pilocarpine-induced status epilepticus

“…Alternatively, hilar astrocytes may be intrinsically more vulnerable to damage than astrocytes in the nearby dentate molecular layer. For example, many hilar astrocytes, in contrast to molecular layer astrocytes, contain Gomoripositive inclusions (Ohm et al, 1992), which originate from transformed mitochondria that become engulfed in lysosomes and contain peroxidase activity, heme, copper and reactive SH groups (Schipper, 1991). These inclusions may be an indicator of chronic oxidative stress (Schipper, 1996), but the cause and role of the inclusions in brain pathology remains largely unclear.…”

The glial Gomori-positive material is sulfane sulpfur.

“…In vivo, numbers of astrocytic granules increase as a function of advancing age, in response to chronic estrogen stimulation, and following X-radiation [17] and after treatment with some xenobiotics [16]. In vitro, these cells accumulate with increasing time in culture and following exposure to the sulfhydryl agent, cysteamine [11]. These cells may contribute to the pathogenesis of several neurologic disorders, especially potentiation of parkinsonism and other free radical-related neurodegenerations [11].…”

“…In vitro, these cells accumulate with increasing time in culture and following exposure to the sulfhydryl agent, cysteamine [11]. These cells may contribute to the pathogenesis of several neurologic disorders, especially potentiation of parkinsonism and other free radical-related neurodegenerations [11]. However, injection of potassium cyanide causes significant decrease in number of GGPM containing glial cells [18], what suggests the role of GGPM in cyanide detoxification.…”

“…The containing sulfur GGPM in periventricular astrocytes appears to be derived from degenerate mitochondria [11]. The aim of this work was to indicate whether most, if not all, of the GGPM is in fact sulfane sulfur.…”

“…These granular inclusions exhibit an affinity for Gomori stains (chrome alum hematoxylin and aldehyde fuchsin) as well as red autofluorescence and non-enzymatic peroxidase activity [9][10][11][12][13]. In the preparations of astrocyte cytoplasmic granules from intact rat brain the smaller granules (0.5-4.0 microns) and larger inclusions (5-10 microns) were observed.…”